APES Unit 4 Summary

  • Plate tectonics are moved by convection

    • The continental crust is thick, oceanic crust is thin

  • Divergent Plate boundary: go away from each other, and magma comes through the crack

  • Strike-slip/transform plate boundary: slide against each other (ex. San Andreas Fault)

  • Convergent plate boundary: one plate goes under the other (ex. Fault that made the Himalayan Mountains)

    • When there is a convergent boundary with both oceanic crust and continental crust, the oceanic crust goes under the continental crust, called subduction (ex. Andes Mountains)

  • Soil horizons: 

    • Organic (O horizon)

    • Topsoil (A horizon)

    • Leaching Layer (E horizon)

    • Subsoil (B horizon)

    • Weathered parent material (C horizon)

    • Bedrock (R horizon)

  • Terracing: step-like terracing is built on slopes. They prevent runoff from rushing downhill and carrying away the soil

  • Strip cropping: groundcover plants such as grasses are planted in strips between fields of crops. These strips soak up water and prevent runoff

  • No-till planting: seeds are planted in the ground without plowing the soil first. Dead plants from the previous harvest remain on the ground, which holds the soil in place

  • Windbreaks: rows of trees are planted between fields. The trees block the wind and prevent wind erosion

  • Contour cropping: crops are planted in curving rows to follow the contour of the hills. This slows runoff and reduces erosion

  • Cover crops: fields are planted year-round, even in seasons when crops don’t grow. The plants cover the soil and hold it in place 

  • Earth’s atmosphere is 78% nitrogen and 21% oxygen

  • Urban heat island: caused by differing ability of building and plant materials to absorb and hold heat. Human activity is also a factor. More heat and smog is trapped in urban areas due to a thermal inversion

  • Coriolis effect: winds in the Northern Hemisphere spin clockwise, and winds in the Southern Hemisphere spin counterclockwise. This is caused by the rotation of Earth on its axis

  • Watersheds: an area of land that drains all the streams and rainfall to a common outlet such as the outflow of a reservoir, bay, channel, etc

  • El Nino: Westerly are weak or non-existent. Warm water moves towards the Eastern Pacific, causing droughts and floods in Australia and Indonesia/SE Asia.  Flooding in Peru/South and Central America

  • La Nina: Eastern Pacific is colder than usual

  • Ecological footprint: rough measure of the amount of biologically productive land needed to sustain each person

    • More developed countries have a larger ecological footprint, less developed countries have a smaller one